Centrifugal machines having a nozzle type rotor structure



March 1963 K. E. JACOBSON 3,080,108

CENTRIFUGAL MACHINES HAVING A NOZZLE TYPE ROTOR STRUCTURE Filed Jan. 12, 1961 2 Sheets-Sheet 1 HIV 1 l llll! I INVENTOR: KENA/Effi E- JHCDBSEN BY Weak AULP/ March 5, 1963 K. E. JACOBSON 3,080,103

CENTRIFUGAL MACHINES HAVING A NOZZLE TYPE ROTOR STRUCTURE Filed Jan. 12, 1961 2 Sheets-Sheet 2 INW'Z'NTOR: KENNETH E.;;'JAcoBsoN ATTORNEY.

structure. an open end providing the primary overflow for the light- United States This invention relates to improvements in centrifugal machines for separating a feed mixture or emulsion into a plurality of liquid fractions of diiferent specific gravities, where an underflow fraction, for instance a solids bearing concentrate, is delivered by discharged nozzles along the outer periphery of the rotor or rotor bowl, while respective lighter liquid fractions discharge by way of respective circular overflows concentric with the rotor axis.

This invention may be embodied in what is termed a three-product machine, that is a machine from which two overflow liquid fractions of different specific gravities discharge at respective opposite constricted ends of the rotor body, and which includes means for returning third fraction underflow material from the nozzles into the separating chamber of the bowl with or without the addition of a wash water or control liquid, or for the introduction of wash water or control liquid alone. i A three-product machine of that general description is capable of producing the two overflow fractions at relatively great purity, namely uncontaminated one by the other, inasmuch as these two overflows are located at the opposed constricted ends of the rotor structure, with the nozzle underflow from the discharge nozzles located midway inbetween and adapted to intercept whatever stray overflow material may occur.

Such a machine may be advantageously employed for example in crude oil separation treatment whereby the separated oil and water discharge from the respective overflows, whereas water-solids mixture or solids carrying concentrate constitute the underflow delivered by the discharge nozzles.

A threeproduct machine adapted to embody this invention is more particularly illustrated in the copending patent application of Honeychurch, Ser. No. 34,303 (Series of 1960), filed June 6, 1960. That application discloses a centrifuge rotor wherein the rotor bowl has trunco-conically shaped end portions constituting an annular centrifugal separating chamber with the underflow discharge nozzles mounted upon the outer periphery thereof, and the respective overflows for the lighter fractions located at the opposed constricted end of this rotor The one conical end portion of the bowl has est fraction, while the opposite portion of this separating chamber is formed with a solid hub portion from which a rotor shaft extends through said open primary overflow end. A complementary annular construction is detachably connected to the rim of this hub portion, including integral annular partition means which in turn have fullfashioned integral radial pumping vanes. In this way, there is formed at the inner side of the partition means a centrally disposed influent'chamber directly adjacent .to said hub portion and thus adjacent to the separating chamber, for receiving underflow return or control liquid or the like engaged by the pumping vanes, whereas at the ary fraction overflow. V p These mutually adjacent concentric influent and efllue'nt chambers in the complementary construction comatent municate with the separating chamber in the bowl through respective sets of conduits which are in the form of the removable tube members. One set of divergent influent tube members is disposed around the rotor axis, leading from the central influent chamber directly through the hub portion into the region of the discharge nozzles for carrying the underflow return or the like, whereas a set of convergent efflnent tube members leads from an inter mediate zone of the separating chamber in the bowl through the hub portion thereof as well as through the influent chamber into the annular discharge chamber for discharging the intermediate or secondary fraction over saidring dam.

The invention more particularly relates to an improved mounting of the tubes in connection with the aforementioned complement-ary construction and other associated parts.

Incorporating the aforementioned detachable complementary annular construction into the rotor structure and placing it in accurate relationship with the respective sets of tube members represents a problem insofar as dynamic balance conditions require a compact threaded connection between the bowl and the complementary construction rather than the use of a bulky flange and bolt connection. This threaded connection in turn involves difficulties with respect to mounting the aforementioned set of convergent tube members which must penetrate through bores or holes in the respective thread-conthe outer ring member and turnably adjustable therein.

This insert member is of special annular configuration defining by its annular hollow space the aforementioned efliuent receiving chamber, and at the same time constituting with the adjacent hub portion of the bowl the central influent chamber for receiving the aforementioned underflow return or the like. This annular hollow insert member, according to the invention, is turnably adjustable about the rotor axis independently of the screwed-in outer ring member to achieve alignment for the convergent set of tube members and upon such adjustment this insert member is held fixed in place together with a detachable ring dam member by means of a common threaded end retainer ring.

According to a feature, the turnably adjustable insert member is unitary with specially shaped radial pumping vanes.

In one embodiment, this insert member is held by the end retainer ring tight in abutting relationship against the associated convergent tubes.

In another embodiment, the position of the convergent tube members longitudinally is secured by thread connec* tion with the insert member.

Other features and advantages will hereinafter appear.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof will be best understood from the following description of specific embodiment when read in connection with the accompanying drawings, in which:

FIG. 1' is a vertical sectional view of a three-product centrifugal machine, illustrating one mode of mounting the convergentset of tubes by the use of the varied insert members of this invention.

.FIG. 2 is a part sectional view taken on line 2-2 of FIG. 1, illustrating the arrangement ofthe two sets of tubes relative to each other, as well as relative to the pumping vanes.

FIG. 3 is a detail vertical sectional view of insert member shown in place in FIG. 1.

'FIG. 4 is an enlarged detail view of the invention illustrating a modified arrangement of the mounting of the tubes.

FIG. 5 is a detail view similar to FIG. 4, illustrating still another modified arrangement of the mounting of the tubes.

An example of a centrifuge machine embodying the inventi-on as shown in FIGS. 1 to 4 comprises a rotor operating in a stationary housing 11. Mounted on top of the housing are means from which the rotor shaft 12 is suspended and mounted for rotation. The means of rotor support being well known are herein indicated only by the fragmentary showing of a top bracket structure 13 carried by the housing.

The rotor bowl embodying features of this invention comprises the so-called rotor bowl which is of generally double-conical configuration having constricted ends 14 and 15 for delivering respective separated liquid fractions as primary overflow 14a and a secondary overflow 15a. This configuration of the bowl, therefore, also comprises an intermediate p0rtiOr11'7 delivering a third fraction or concentrate also termed underflow 17a through well known discharge nozzles 18 mounted in this outer peripheral portion of the bowl. In the example of FIG. 1, feed mixture or emulsion with solids may enter-the rotor at 19 through the primary overflow end thereof while control liquid or recirculating underfiow may enter the rotor through the opposite end from an injection nozzle device 20 including return flow regulating means 20a,

More particularly, the construction of the rotor bowl in this embodiment comprises a hub portion 21 fixed to shaft 12 and shown to be integral with one trunco-conieal end portion 22 of the bowl. The wide end of this end portion constitutes a'cylindrical rim 23 preferably formed with an inner peripheral race or groove 24 communicating with the discharge nozzles 18'mounted in this rim. An opposite trunco conical end portion 24a of the bowl has its wide end tightly; although detachably, connected to the-wide end of the conical end portion 22, being fitted into the rim 23 and secured thereto as by well-known securing means such as a spreader ring indicated at 25. At its constricted end the conical end portion 24 of the rotor bowlterminates in a cylindrical portion 26 which in turn provides an overfiow lip 27 for the aforementioned primary overflow 14a.

The huo'portion 21 together with the two trunco-conical end portions of the bowl constitutesa centrifugal separating chamber 28 wherein there is mounted a feed inlet member or receiving well member 29 comprising a substantially cylindrical well portion 30 and a conical or flaring foot portion 3-1 seated upon the correspondingly conical face 32 of the hub portion 21 and held in place as at 3 1a by pressureco-nt-act with the conical end portion 24 of the bowl. The feedwell member 29 thus provides around the shaft a feed inlet passage33 into'which may extend an annular feed supply conduit 34 surrounding the shaft, formed by concentric tubes 34aand 34b. Feed mixture from this feedwell passes through divergent feed passages 35 into the separating chamber which may have perforated tubes 36 distributing the feed mixture cooperaitvely associated with a stack of separating discs 37. The function of these discs together with the tubes 36 is well known in that they help separate and reject fine-solids or other relative heavier component materials carried-by the light liquid fraction as it passes-through the interstices between the' discs-for discharge through the. primary over flow 14a. v

Detachably' connected to thehub portion 21 is a compartmented complementary construction 38 constituting 'cated infiuent chamber 39' forreceiving control liquid or returning underfiow material, and surrounding it is an annular discharge chamber 40 collecting and discharging the secondary liquid fraction as over a ring dam member 41.

According to this invention, the complementary construction 38 in the rotor comprises a complementary ring member 42 consisting of a trunco-conical inner end'portion 43 and a cylindrical outer end portion 44 extending from theconstricted. endofthe portion 43. The trunco-conical inner end portion has external thread whereby this ring member is screwed into an internally threaded rim portion 44a against a gasket 45, the rim portion being formed at the junction of the hub portion 21 with the adjacent wall portion of the rotor bowL' The cylindrical portion 44 has thread engagement with an internally threaded retainer ring 46. A novel hollow annular insert member 47 fits into the cylindrical outer end portion of the ring member 42 and is held in place therein by the retainer ring. This insert member 47 defines within itself the aforementioned annular discharge chamber 40, and also defines together with the hub portion 21 and with the adjoining trunco-conical portion 43 of the complementary ring member and with the exposed part of the insert member- 47 the centrally located infiuent chamber 39. I a

The insert member 47 as illustrated in the embodiment of FIG. 1 is seatedin the ring member 42 as against an abutment face 48, so as to be turnably positionable-in rder that openings 49 in the insert member (see detail FIG. 3) may be brought into registry with respect to corresponding openings in the hub portion 21, to provide for further mountingtherein of tubular members or tubes presently to be described.

There is aset of divergent infiuent tubes 50 mounted in the hub portion 21 of the rotor bowl for carrying control liquidor wash liquid or recirculating underflow from the central influent chamber 39 to the region of the discharge nozzles in the separating chamber. There is further a set of convergent efiluent tubes 51 aligned with the openings- 49 in the insert member, which tubes extend through the influent chamber and on through the hub portion into the separating chamber of the bowl for carrying an intermediate liquid fraction from an intermediate zone in the separating chamber out into-the annular efilue'nt chamber 40 for discharge over the-ring dam member 41. As herein illustrated, both sets oftubes 50 and 51 carrying liquid in respective opposite directions are arranged around the rotor axis in alternation and substantially in the identical conical alignment as well as adjacent to the Wall of the respective trunco-conical portion22 of the rotor bowl. 7

Since the convergent efiluenttubes 51 extend through the influent chamber 39,. they constitute between them recesses 52 (see detail FIG. 2) through which the control liquid or the like will reach and enter the divergent infiuent tubes 50. Radial pumping vanes 53 in this embodiment are provided on the insert member 47 for urging control liquid or returning underfiow from the influent chamber 39 through the divergent influent tubes 50 into the separating chamber of the bowl.

The insert-member 47 cooperates with the ring darn member 41, both. being held in place in the ring member 42 by means of a common member, namely the retainer ring 46 in the structural arrangement of the invention.

The hollow annular insert member 47 itself (see FIG. 3) in this embodiment comprises an outer cylindrical wall portion 47a, an intermediate trunco-conical Wall portion 47b extending from the inner end of the cylindrical portion and with its constricted enddirected towards the hub portion of the bowl,- and a frusto-conicalend wall portion 470 extending from the constricted end of the In this way, the" insert member 47 together with the ring dam member 41 defines the aforementioned efiluent chamber 40 as well as the central influent chamber 39, the ring dam member extending as far inwardly as is necessary relative to the eflluent end of tubes 51 and also to an extent providing an overflow diameter suitably greater than the overflow diameter of the primary overflow 27. Accordingly, the central influent chamber 39 is definable more precisely as being formed by the hub portion 21, the frusto-conical portion 43 of ring member 42, the intermediate trunco-conical portion 47b of the insert memher, and the frusto-conical end wall portion of the insert member.

Thus, with the insert member 47 being turnably adjustable relative to the hub portion 21, the assembly of the parts arranged according to this invention may be carried out conveniently as follows: before attaching the entire complementary construction 38 to the rotor bowl, the convergent efiiuent tubes 50 are inserted in the hub portion, their position in this instance being determined by a rim or stop bead 47d formed at the influent end of the tubes. Then, the ring member 42 is screwed and tightened into the threaded portion of the bowl, whereupon the insert member 47 may be positioned in this ring member ready for the convergent tubes 51 to be inserted to a position defined by their stop rim or bead 47a. The assembly is then completed by placing the ring dam member 41 against the insert member and attaching and fastening the retainer ring for holding both. Of course, it is also possible to first loosely assemble the insert member as well as the darn ring member and the retainer ring, and then inserting the tubes 51, followed by tightening the retainer ring.

The housing in the embodiment of FIG. 1 has separate discharge outlets for the three separated fractions and accordingly has a top receiving chamber 54 provided with an outlet 55 for the primary overflow, a bottom receiving chamber 56 provided with an outlet 57 for the secondary overflow, and an intermediate volute chamber 58 with outlet 59 for discharging underflow material from the nozzles. In the embodiment shown, the housing is subdivided into structural sections which comprise a cylindrical section 60 formed with an annular partition 61 and also with the outlet 55, a top cover portion 62 fastened to the upper end of the cylindrical section and carrying the aforementioned bracket structure 13 for supporting the rotor, a volute section 63 fastened to the lower end of the cylindrical section and formed with the outlet 59, and a conical bottom section 64 fastened to the lower end of the volute section and formed with the outlet 57. Moreover, this embodiment shows an external return conduit 65 for recirculating underflow from the nozzles back into the rotor through the injection device 20, 29a, with an underflow discharge control valve 66 operable to control the recirculation rate and thus the concentration of the underflow. Additional control liquid or wash water or the like may be introduced into the underflow return circuit as by means of a valve 67. The return conduit 65 has an additional valve 68 whereby recirculation therethrough may be interrupted while underflow discharge through valve 66 and the introduction of the control liquid through valve 67 may be operated individually. The separation of the intermediate fraction from the light fraction may be aided by separating discs 37 the function of which of itself is well known in the art.

According to the invention, the enlarged detail FIG- URES 4 and 5 illustrate other ways of mounting the convergent flow transfer tubes, with means of securing them relative to the insert member and other associated parts of the rotor structure.

Thus, in FIG. 4, all parts are here designated by the same numerals as corresponding parts in FIG. 1, excepting the insert member and the associated tubes, identified by numerals 477 and 58a. In this embodiment, the securing means of the tubes comprise a thread connection 50b and a threadlocking terminalrim or bead 50c formed at the elfluent end of the tubes. This insert member 47 also ditfers from the one shown in FIG. 1- in that it is formed with a small outer flange or shoulder 47g confined between the ring member 42' and the overflow ring dam member 41, thereby securing theinsert member shown to be provided with pumping vanes 47h preferably shaped with the contour herein illustrated. According to FIGURE 4, therefore, the outer cylindrical wall portion of the insert member provides a shoulder portion confined between the complementary ring member 42 and the ring dam member 41, when the'retainer ring member 46 is tightened upon the external thread on ring member 42.

Considering the embodiment in detail FIG. 5, again the parts are numbered identical to those in FIG. 4, but with the exception of the insert member which is here designated 471 and differs from those in FIG. 1 and FIG. 4 in that it is provided with plain holes 47k which need not be substantially greater than the inside diameter of the associated tubes here designated 50a. The influent end Site of these tubes has for example a partial extension 50] providing an abutment face cooperating with the companion abutment face 50g on the rotor bowl, 'while the eflluent end 5011 has pressure engagement with a respective abutment face on the insert member which in turn holds the tubes thus confined between the respective abut- 'said insert member to be axially confined between said ring dam member and said divergent tubular members, and further causing said divergent tubular members themselves to be longitudinally confined between abutment faces on the insert member and abutment faces on the bowl respectively.

In the operation of the machine itself as illustrated in FIGS. 1 to 4, the feed mixture or emulsion enters'the rotor through the'stationary annular feed conduit 34 which extends into the feed inlet passage 33 within the rotor, whence the mixture passes on through downwardly divergent feed passages 35 into the separating chamber 28 of the rotor bowl. Rotation of the bowl will cause separation of the components of the mixture, into three ractions of different specific gravities, namely a sludge tom into the influent chamber 39 where the pumping vanes 53 will insure that this suspension enters the di vergent transfer tubes 50 for delivery in the region of the nozzles. Adjusting the rate of sludge draw-off at valve 66 will correspondingly influence the concentration of the underflow, in that a decrease in the rate of draw-oil will increase the concentration. Wash liquid may be added to the sludge return, or wash liquid may be used alone. However, it will be understood that the nozzle flow requirements may be satisfied by recirculating nozzle discharge or by. the addition of wash liquid from another source, to establish a suitable interface for maintaining light fraction separation. For example, crude oil may thus be separated into an oil fraction, a water fraction, and a concentrate which latter may consist of water containing solids such as sand and other particles.

From the foregoing, it will be seen that the invention provides in a centrifugal machine preferably of the threeaosonos product type-having underfiow discharge nozzles, an improved r-otor construction featuring a novel and highly practical structural assembly and relationship of parts, which assembly defines the central influent chamber for underflow return and the annular efiluent chamber surrounding it for deliveringthe intermediate fraction derived through the divergent tubes. The separate insert member being turnably adjustable within that assembly provides the advantage of rendering the mounting of the convergent tubes independent of the degree of compressibility of the gasket 45 located between the ring member 42 and therim portion 44a of the rotor bowl.

It will be understood that each of the elements described above pertaining to the invention, or two or more together may also find useful application in other centrifugal machines differing from the type described above.

While the invention has beenillustrated and described as embodied in a three-product nozzle type centrifugal machine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of this invention.

As this invention may be embodied in several forms without departing from the spirit of essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the claims.

I claim:

I. In a centrifuge rotor having a separating chamber of double cone-shaped configuration defined by a rotor bowl provided with underflow discharge nozzles at the outer periphery thereof located between the constricted ends of the bowl, said bowl having a hub at one constricted end and having primary overflow means at the opposi-te constricted end, with a rotor shaft extending axially from said hubthrough the area defined by said primary overflow, said rotor also having means for discharging a secondary overflow fraction from the hub end portion of the bowl, as well as means for returning underflow material into the separating chamber at said hub end portion of the bowl, the arrangement which comprises an internally threaded rim portion located at the hub end portion of the rotor bowl; a complementary ring member comprising a frusto-conical end portion having the wide end thereof thread-connected to said threaded rim portion and also comprising a cylindrical end portion extending outwardly axially from the narrow end of said frusto-conical end portion and having an external thread; a hollow annular insert member surrounded by said complementary ring member, comprising a cylindrical outer wall portion providing a shoulder portion and fitted into said cylindrical endportion of the complementary ring member, an intermediate wall portion extending inwardly from the inner end of said cylindrical wall portion and having predetermined communication openings, and an inner wall portion extending from the inner end of said intermediate wall portion and directed away from said hub; a ring dam member surrounding said inner end wall portion of the insert member in concentrically spaced relationship therewith and located adjacent to the outer'end of said outer wall portion of the insert member, and constituting with said hollow insert member an annular discharge chamber for secondary overflow from the separating chamber, said inner end wall portion together with said intermediate portion of 'the insert member and with said frustoconical portion and with said hub providing a central influent chamber for receiving return underflow material; an internally threaded retainer ring member engaging respective external thread of the complementary ring memher and effective when tightened upon said external thread -to engage said ring' dam member and. to cause. said shoulder portion of the insert member to be axially confined between said ring dam member and said complementary ring member; a set of convergent tubular members arranged around the rotor axis in registry with said respective communication openings, and detachably connected to said insert member and extending through said hub to provide communication between said annular discharge chamber and said separating chamber for discharging an intermediate fraction of secondary overflow material into said annular discharge chamber and outacross said ring dam member; a set of divergent tubular members arranged around the rotor axis in alternation with said convergent tubular members and extending through said hub and providing communication between said central infiuent chamber and said separating chamber for the return of underflow material from said central influent chamber into the region of the nozzles in the separating chamber, and pumping vanes provided in said central influent chamber and effective to impel return underflow material into and through said divergent tubular members for delivery in said separating chamber.

2. The arrangement according to claim 1, wherein said pumping vanes are provided on said insertmember.

3. In a centrifuge rotor having a separating chamber of double-cone shaped configuration defined by a rotor bowl equipped with underflow discharge nozzles at the outer periphery thereof located between the constricted ends of the bowl, said bowl having aprimary overflow at one constricted end for discharging one overflow fraction, and having a hub at the opposite constricted end, with a rotor shaft extending from saidhub through the area defined by said primary overflow, said rotor also having means for discharging secondary overflow material as an intermediate fraction, as well as means for returning underfiow material from the nozzles into the separating chamber, the arrangement which comprises an internally threaded rim portion located at the hub end portion of the rotor bowl; a complementary ring member formed with a frusto-conical end portion having the wide end thereof thread-conneeted to said threaded rim portion and also comprising a cylindrical end portion extending outwardly axially from the narrow end of the frusto-conical portion and having an external thread; a hollow annular insert member surrounded by said complementary ring member, comprisinga cylindrical outer wall portion fitted into said cylindrical end portionof the complementary ring member, an intermediate wall portion extending inwardly from the inner end of said outer cylindrical wall portion and having predetermined communication openings, and an inner end wall portion extending inwardly from the inner end of the intermediate wall portion and directed away from said hub; a ring dam member adjacent to the outer end of said cylindrical portion of the insert member while surrounding said inner end wall portion of the insert member in concentrically spaced relationship therewith, and constituting with said hollow insert member an annular dischargechamber for secondary overflow from the separating chamber, said inner end, wall portion together with said intermediate portion of the insert member and with said frusto-conical portionand with said hub providing a central infiuent chamber for receiving return. underflow material; means providing abutment faces on said ,rotor bowl and on saidinsert member respectively; a set of convergent tubular members extending through said hub and arranged around the rotor axis and having an influent end located in said separating chamber, and registering with said communication openings in the insert member for discharging secondary overflow material from the separating chamber into said annular discharge chamber and out across said ring dam member, said convergent tubular members being confined between respectivea'butment faces on the rotor bowl and on the insert member; a set of divergent tubular members arranged around the rotor axis in alternation with said convergent tubular members and extending through said hub and providing communicationbetween said central 9 infiuent chamber and said separation chamber for the return of underflow material from said central influent chamber into the region of the nozzles in the separating chamber; an internally threaded retainer ring member engaging the respective external thread of the complementary ring member and effective when tightened upon said external thread to engage said ring darn member, thereby causing said insert member to be axially confined between said ring dam member and said divergent tubular members and further causing said divergent tubular members themselves to be longitudinally confined between said abutment faces on the insert member and on the :bowl respectively; and pumping vanes provided in said central iniluent chamber and efiective to impel underfiow return material from said central chamber into and through said divergent tubular members for delivery in said separating chamber.

4. The arrangement according to claim 3, wherein said pumping vanes are provided on said hollow annular insert member.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A CENTRIFUGE ROTOR HAVING A SEPARATING CHAMBER OF DOUBLE CONE-SHAPED CONFIGURATION DEFINED BY A ROTOR BOWL PROVIDED WITH UNDERFLOW DISCHARGE NOZZLES AT THE OUTER PERIPHERY THEREOF LOCATED BETWEEN THE CONSTRICTED ENDS OF THE BOWL, SAID BOWL HAVING A HUB AT ONE CONSTRICTED END AND HAVING PRIMARY OVERFLOW MEANS AT THE OPPOSITE CONSTRICTED END, WITH A ROTOR SHAFT EXTENDING AXIALLY FROM SAID HUB THROUGH THE AREA DEFINED BY SAID PRIMARY OVERFLOW, SAID ROTOR ALSO HAVING MEANS FOR DISCHARGING A SECONDARY OVERFLOW FRACTION FROM THE HUB END PORTION OF THE BOWL, AS WELL AS MEANS FOR RETURNING UNDERFLOW MATERIAL INTO THE SEPARATING CHAMBER AT SAID HUB END PORTION OF THE BOWL, THE ARRANGEMENT WHICH COMPRISES AN INTERNALLY THREADED RIM PORTION LOCATED AT THE HUB END PORTION OF THE ROTOR BOWL; A COMPLEMENTARY RING MEMBER COMPRISING A FRUSTO-CONICAL END PORTION HAVING THE WIDE END THEREOF THREAD-CONNECTED TO SAID THREADED RIM PORTION AND ALSO COMPRISING A CYLINDRICAL END PORTION EXTENDING OUTWARDLY AXIALLY FROM THE NARROW END OF SAID FRUSTO-CONICAL END PORTION AND HAVING AN EXTERNAL THREAD; A HOLLOW ANNULAR INSERT MEMBER SURROUNDED BY SAID COMPLEMENTARY RING MEMBER, COMPRISING A CYLINDRICAL OUTER WALL PORTION PROVIDING A SHOULDER PORTION AND FITTED INTO SAID CYLINDRICAL END PORTION OF THE COMPLEMENTARY RING MEMBER, AN INTERMEDIATE WALL PORTION EXTENDING INWARDLY FROM THE INNER END OF SAID CYLINDRICAL WALL PORTION AND HAVING PREDETERMINED COMMUNICATION OPENINGS, AND AN INNER WALL PORTION EXTENDING FROM THE INNER END OF SAID INTERMEDIATE WALL PORTION AND DIRECTED AWAY FROM SAID HUB; A RING DAM MEMBER SURROUNDING SAID INNER END WALL PORTION OF THE INSERT MEMBER IN CONCENTRICALLY SPACED RELATIONSHIP THEREWITH AND LOCATED ADJACENT TO THE OUTER END OF SAID OUTER WALL PORTION OF THE INSERT MEMBER, AND CONSTITUTING WITH SAID HOLLOW INSERT MEMBER AN ANNULAR DISCHARGE CHAMBER FOR SECONDARY OVERFLOW FROM THE SEPARATING CHAMBER, SAID INNER END WALL PORTION TOGETHER WITH SAID INTERMEDIATE PORTION OF THE INSERT MEMBER AND WITH SAID FRUSTOCONICAL PORTION AND WITH SAID HUB PROVIDING A CENTRAL INFLUENT CHAMBER FOR RECEIVING RETURN UNDERFLOW MATERIAL; AN INTERNALLY THREADED RETAINER RING MEMBER ENGAGING RESPECTIVE EXTERNAL THREAD OF THE COMPLEMENTARY RING MEMBER AND EFFECTIVE WHEN TIGHTENED UPON SAID EXTERNAL THREAD TO ENGAGE SAID RING DAM MEMBER AND TO CAUSE SAID SHOULDER PORTION OF THE INSERT MEMBER TO BE AXIALLY CONFINED BETWEEN SAID RING DAM MEMBER AND SAID COMPLEMENTARY RING MEMBER; A SET OF CONVERGENT TUBULAR MEMBERS ARRANGED AROUND THE ROTOR AXIS IN REGISTRY WITH SAID RESPECTIVE COMMUNICATION OPENINGS, AND DETACHABLY CONNECTED TO SAID INSERT MEMBER AND EXTENDING THROUGH SAID HUB TO PROVIDE COMMUNICATION BETWEEN SAID ANNULAR DISCHARGE CHAMBER AND SAID SEPARATING CHAMBER FOR DISCHARGING AN INTERMEDIATE FRACTION OF SECONDARY OVERFLOW MATERIAL INTO SAID ANNULAR DISCHARGE CHAMBER AND OUT ACROSS SAID RING DAM MEMBER; A SET OF DIVERGENT TUBULAR MEMBERS ARRANGED AROUND THE ROTOR AXIS IN ALTERNATION WITH SAID CONVERGENT TUBULAR MEMBERS AND EXTENDING THROUGH SAID HUB AND PROVIDING COMMUNICATION BETWEEN SAID CENTRAL INFLUENT CHAMBER AND SAID SEPARATING CHAMBER FOR THE RETURN OF UNDERFLOW MATERIAL FROM SAID CENTRAL INFLUENT CHAMBER INTO THE REGION OF THE NOZZLES IN THE SEPARATING CHAMBER, AND PUMPING VANES PROVIDED IN SAID CENTRAL INFLUENT CHAMBER AND EFFECTIVE TO IMPEL RETURN UNDERFLOW MATERIAL INTO AND THROUGH SAID DIVERGENT TUBULAR MEMBERS FOR DELIVERY IN SAID SEPARATING CHAMBER. 